Study of certain enzymes and other proteins that consist of multiple subunits and that assemble into macromolecular functional units. Major emphasis on amino acid sequences of glutamate dehydrogenases, flagellins, phycobiliproteins, histones and other chromosomal proteins. The role of various residues important to the self-assembly and other functions of these proteins are being studied. Flagellins and phycobiliproteins represent simple systems for the study of organelle assembly. In each instance, the proteins assemble spontaneously to form a cellular organalle. Histones function by interaction with DNA and with other chromosomal proteins. The nature and role of in vivo modifications of the amino acid side chains is being pursued. Glutamate dehydrogenases are high molecular proteins that consist of multiple, identical subunits. These enzymes play a key role in regulation of amino acid metabolism in all species.